60' LFMC Equip. grounding conductor

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steve66

steve66

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Location
Illinois
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Engineer
I peeked inside an existing panelboard, and saw green and white wires landed on the same bus. Then I noticed the feeder was only 3 phase wires and a neutral - no ground wire. I followed the feeder. It starts out as metal conduit. But then it changes to liquidtight flexible metal conduit for the last 60' of the run (that's so much easier than bending conduit and using fittings!!)

Can I have the contractor run an EGC on the outside of the LFMC and terminate it on the switchboard and the conduit?? What about 250.120(C), which requires protection for EGC's smaller than #6 (this would be a #8)? Can I have the contractor run AC cable on the outside of the LFMC?
 
Re: 60' LFMC Equip. grounding conductor

How long was the metal conduit,was there an MIG bushing ?
 
Re: 60' LFMC Equip. grounding conductor

Steve
Can I have the contractor run an EGC on the outside of the LFMC and terminate it on the switchboard and the conduit??
Click to expand...
Take a look at 300.3(B).
(B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).
Click to expand...
Don
 
Re: 60' LFMC Equip. grounding conductor

Section 250.118 covers the EGC. It can be metallic conduit or conductor. Fexible raceways can have the EGC on the exterior but limited to 6ft. The EGC is required to be with the circuit conductors as Don points out to keep the impedance of the fault current return path low.
 
Re: 60' LFMC Equip. grounding conductor

Section 250.118 covers the EGC. It can be metallic conduit or conductor. Fexible raceways can have the EGC on the exterior but limited to 6ft. The EGC is required to be with the circuit conductors as Don points out to keep the impedance of the fault current return path low.
 
Re: 60' LFMC Equip. grounding conductor

The metal conduit was probably another 60' long. The transition from LFMC to RGS takes place at a pull box up high, so I can't tell if there is a MIG bushing.

Yes, it looks like the EGC would have to be in the LFMC. Looks like I was reading paragraphs that apply to open runs of wire, like ROMEX. It is possible that there is a 4th wire that terminates at the pull box, but I will have to have the contractors verify that.

Steve
 
Re: 60' LFMC Equip. grounding conductor

A fool wouldn`t run carflex without a ground wire,unless green as grass.
 
Re: 60' LFMC Equip. grounding conductor

There may be a ground conductor in the LFMC, and I'll have the contractor be sure. But why only run the ground wire half-way instead of continuing it through the conduit also? And I really think it is suspicious that there is no separate ground bus in the panel. I'm thinking that this may be because there is no ground connection.
 
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